Along with the rapid distribution of information-related equipment and communication equipment such as personal computers, video cameras, and mobile telephones in recent years, the development of batteries that are utilized as electric power sources thereof has been considered important. Furthermore, the development of high output power and high capacity batteries for electric vehicles or hybrid vehicles is in progress in the field of automobile industry and the like as well. Currently, among various batteries, lithium batteries are attracting attention because of its high energy densities.
In regard to the lithium batteries that are currently available in the market, since liquid electrolytes including flammable organic solvents are used, installation of safety devices that suppress temperature increase at the time of short circuits, and devices for preventing short circuits are needed. Meanwhile, since lithium batteries that have been produced into all solid state batteries by converting the liquid electrolyte to a solid electrolyte layer do not use flammable organic solvents in the batteries, it is contemplated that simplification of safety devices can be promoted, and the lithium batteries are excellent in view of the production cost and productivity.
As a solid electrolyte that can be used in the all solid lithium battery, a sulfide solid electrolyte is known. For example, Patent Literature 1 discloses a sulfide-based solid battery in which an anode active material layer contains anode active material fine particles and sulfide-based solid electrolyte fine particles, and a ratio (ra/rs) of an average particle size (ra) of the anode active material fine particles to an average particle size (rs) of the sulfide-based solid electrolyte fine particles is 2.0 or greater. An object of this technology is to provide a sulfide-based solid battery having high charging and discharging capacity with respect to charging and discharging, particularly, under high current density conditions.